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CVE-2026-44293 high CVSS 8.8

Code Injection in protobufjs (CVE-2026-44293)

Summary

Code injection in protobufjs (CVE-2026-44293). Successful exploitation can lead to full system takeover. Exploitable via toObject. Mitigation: upgrade to 8.0.2 or later.

Original description

The description as published by the source.

Summary

protobufjs generated JavaScript for toObject conversion could include an unsafe expression derived from a schema-controlled bytes field default value. A crafted descriptor with a non-string default value for a bytes field could cause attacker-controlled code to be emitted into the generated conversion function.

Impact

An attacker who can provide or influence a protobuf descriptor may be able to execute arbitrary JavaScript in the context of the process using protobufjs.

This requires the application to load an attacker-controlled schema or descriptor and then convert a message of the affected type with defaults enabled. Applications that only use trusted, application-defined schemas are not directly affected by this issue.

Preconditions

  • The application must allow an attacker to control or influence a protobuf JSON descriptor or equivalent reflected schema.
  • The descriptor must define a bytes field with an attacker-controlled default value.
  • The application must call toObject with defaults enabled for the affected type.

Workarounds

Do not load protobuf schemas or JSON descriptors from untrusted sources with affected versions. If untrusted schemas must be accepted, validate or restrict field options before loading them and run schema processing in an isolated environment.

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-44293 has been found in protobufjs.
Attackers can target a specific entry point like toObject over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade protobufjs to 8.0.2 or later.
If unsure, ask your IT team or search "protobufjs CVE-2026-44293" on the vendor's site.

CVE-2026-44293 (protobufjs) — CWE-94 / CVSS v3 8.8
Attack vector: remote (network-reachable) / no user interaction
Attack surface: toObject / bytes
Patched: 8.0.2 — apply immediately
Workaround: Do not load protobuf schemas or JSON descriptors from untrusted sources with affected versions.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

Arbitrary code execution (CWE-94) exists in protobufjs. Attackers reach the vulnerable code path via toObject.

📍 Affected scope

Check the vendor advisory for the affected versions of protobufjs. Attack surface: toObject / bytes.

🔥 Severity

Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 8.0.2.

🛡️ Workaround

Workaround: Do not load protobuf schemas or JSON descriptors from untrusted sources with affected versions.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'protobufjs' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'protobufjs' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で protobufjs を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply temporary workaround mitigate 
    Do not load protobuf schemas or JSON descriptors from untrusted sources with affected versions.

    パッチが適用されるまでの応急処置として、Do not load protobuf schemas or JSON descriptors from untrusted sources with affected versions. を実施。回避策の副作用 (機能低下) を確認した上で。

  3. 3
    Apply patch patch 
    Upgrade protobufjs to 8.0.2

    ステージング環境で 8.0.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  4. 4
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

npm protobufjs
[{"type":"SEMVER","events":[{"introduced":"8.0.0"},{"fixed":"8.0.2"}]}]

References

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